This invention relates to collars useful in protecting animals against arthropods.
Animals are commonly treated to control fleas and ticks by spraying the coats of the animals with, or dipping the animals in, an insecticide solution. This type of treatment provides temporary protection, usually lasting about three weeks.
Alternately, an insecticidal ear tag is used. The tag releases insecticide as it rubs against the animal""s coat. U.S. Pat. No. 4,606,478 refers to an ear tag which has a reservoir containing a liquid pesticide.
For dogs and cats, collars containing insecticidal compositions have been used to protect against fleas and ticks. U.S. Pat. Nos. 2,205,711 and 4,068,624 refer to collars having chemical insecticide embedded in the material that forms the collar. Other types of insecticidal collars for animals and plastic or resinous insecticide compositions for use in those collars are referred to in U.S. Pat. Nos. 2,808,030; 3,477,409; 3,814,061; 3,852,416 and 3,904,746.
Amitraz is a monoamine oxidase inhibitor (MAOI) used as an insecticide in collars that, as currently marketed, provide about four months of tick protection. Such collars are formed of an extruded matrix containing about 9% by weight of amitraz. As compared with fipronil, amitraz has been found to exert a significantly greater effect on numbers of live feeding ticks, egg hatchability, and larval viability. Estrada-Pena and Ascher, J. Am. Vet. Med. Assn., 1999, 214:1799.
However, a number of dogs consume their amitraz containing collars, resulting in amitraz toxicosis. Symptoms of amitraz toxicosis include incoordination, depression, high blood sugar level, slow heart rate, and decreased body temperature. In severe cases, death may result. Affected dogs are often injected intramuscularly with atipamezole, an alpha-2 adrenoceptor antagonist which has been found to be effective in reversing effects of amitraz toxicosis. Hugnet et al., Am. J. Vet. Res., 1996, 57:1506.
The present invention relates to an insecticidal pet collar comprising 0.1 to 40% by weight of amitraz, or a pharmaceutically acceptable salt thereof, and atipamezole wherein said atipamezole is present in a concentration sufficient to ameliorate poisoning of said pet upon ingestion by said pet of said collar.
In one embodiment, the atipamezole and atropine are incorporated into a matrix in the collar. For example, the collar can comprise a matrix formed of a polymer selected from the group consisting of polyvinyl chloride, polyolefin, polyurethane, polyamide, methacrylate, and silicon polymers. The collar is preferably formed in an extrusion process.
In another embodiment, the pet collar comprises 0.01 to 1%, preferably 0.1 to 1%, by weight of atipamezole. In a further embodiment, the pet collar comprises a matrix having therein about 9% by weight of amitraz. In yet another embodiment, the pet collar has a length of about 25 inches and contains amitraz in a concentration of about 100 mg/inch. In a further embodiment, the atipamezole is contained in a gastric labile coating.